Electronic component mounting method and apparatus

ABSTRACT

The behavior of a nozzle tip is measured with a jig when the suction nozzle moves vertically and rotatively before the start of production. The nozzle tip displacement is formulated from the results with a component thickness and a mounting angle used as parameters, and the parameters are corrected according to the component thickness and the final mounting angle of the electronic component to be mounted in the production stage.

This application is a Divisional Application of Ser. No. 09/094,982,filed Jun. 15, 1998, now U.S. Pat. No. 6,158,117.

BACKGROUND OF THE INVENTION

The present invention relates to a component mounting method andapparatus for automatically mounting components onto a circuit board.

An example of the construction of a prior art generic electroniccomponent mounting apparatus is shown in FIG. 7, and a flowchart of itsoperation control sequence is shown in FIG. 8. With reference to theseFIGS. 7 and 8, a prior art electronic component mounting method will bedescribed.

As shown in FIG. 9, a plurality of mounting patterns 2 a, 2 b, 2 c, etc.and target marks 3 a, 3 b, 3 c, etc. are formed on a circuit board 1,and the production of the circuit board is performed by mounting adesired electronic component on the mounting patterns 2 a, 2 b, 2 c,etc. In this case, the target marks 3 a, 3 b, 3 c, etc. are used forcorrecting the mounting positions which delicately vary on every circuitboard 1 depending on a contraction of the circuit board occurring incalcining the mounting patterns 2 on the circuit board 1, and dependingon the state in which the circuit board 1 is supported by a circuitboard positioning device 4.

The production of the circuit board by means of the electronic componentmounting apparatus is performed firstly by forming mounting data fromthe mounting pattern of the circuit board 1 to be produced (Step #1).FIG. 10 shows an example of the mounting data. Further, a positionalrelation between the mounting patterns and the target marks of thecircuit board for reference use is detected and mark data is formed(Step #2). FIG. 11 shows an example of the mark data.

According to these various data, a specified number of circuit boardsare produced. A production procedure is to firstly bring the circuitboard 1 from a board conveyance section 5 into a circuit boardpositioning device 4 (Step #3). Next, a board image pickup device 6 isaligned in position with the desired target mark 3 a, 3 b, 3 c, etc. ofthe circuit board 1 from above to pickup the image of the target mark 3a, 3 b, 3 c, etc. and the target mark position of the circuit board 1 isdetected. According to this image pickup result, the mounting positionand the angle are corrected (Step #4).

Subsequently, the electronic component mounting head 7 is moved onto acomponent supply device 8 (component supply units 8 a or 8 b) by an XYrobot 20 including an X-direction driving unit 20 x for moving the head7 in an X direction and two Y-direction driving units 20 y for movingthe X-direction driving unit 20 x and the head 7 in a Y directionperpendicular to the X direction. Then, a suction nozzle 9 ofthe head 7is positioned in a component supply position, and the desired electroniccomponent corresponding to the mounting data is sucked (Step #5). Inthis case, the vertical and rotative movements of the suction nozzle 9in the electronic component mounting head 7 are achieved by a mechanismas shown in FIG. 12, where the suction nozzle 9 moves vertically whilebeing interlocked with a shaft 10 and the vertical movement is effectedwith an actuator 11 used as a drive source. In this stage, a locus ofthe shaft 10 when it moves vertically is regulated by a nut 12 and a nut13. Further, the suction nozzle 9 rotates while being interlocked withthe shaft 10, and its rotative movement is effected with an actuator 15used as a drive source via a belt 14.

Next, the electronic component mounting head 7 is moved so that thesucked electronic component is positioned above a component image pickupdevice 16, and the suction posture of the electronic component sucked bythe suction nozzle 9 is detected by the component image pickup device16. Based on this image pickup result, the final mounting position andangle of the electronic component are determined (Step #6).

Finally, by positioning the electronic component mounting head 7 so thatthe electronic component is positioned in the obtained mounting positionon the circuit board and moving the suction nozzle 9 downward, themounting of the electronic component is performed (Step #7).

Thus one circuit board is produced by repetitively performing such aseries of sucking and mounting operations according to the preparatorilyformed mounting data, and it is determined whether or not the productionof the circuit board has been completed at this point of time (Step #8).When the production has been completed, the circuit board is brought outof the circuit board positioning device 4 to the board conveyancesection 5 (Step #9). When the production has not been. completed, thesucking and mounting operations of the next electronic component will beachieved. (Steps #5 through #7).

However, the shaft 10 has a bending attributed to the processingaccuracy as shown in FIG. 13. Accordingly, a displacement of average5-10 μm (increasing toward the nozzle tip in relation to the nut 13)occurs when the shaft 10 is moved vertically by the actuator 11. Thesuction posture of the electronic component is detected by the componentimage pickup device 16, and the suction nozzle 9 is moved down for themounting of the electronic component in the mounting position on whichthe image pickup result is reflected. Therefore, the displacement ofaverage 5-10 μm occurs at the nozzle tip and this causes a problem inthat the electronic component cannot be mounted in the desired mountingposition. 10% or more of all recognition errors might be due to thedisplacement.

In this case, it can be considered to make the component recognitionheight equal to the mounting height for the purpose of preventing thedisplacement of the nozzle tip. In this case, it is required to firstmove the suction nozzle 9 up after recognizing the component, andthereafter move the nozzle down for the achievement of mounting.Therefore, a worthless vertical movement of the suction nozzle 9 occurs,thereby reducing productivity. Then, in order to eliminate the worthlessvertical movement of the suction nozzle 9, the mounting height isgenerally set below the component recognition height so that the suctionnozzle 9 can be moved down from the recognition height after therecognition of the component directly to the mounting height for theachievement of the mounting of the electronic component.

Further, when a rotative deviation occurs through the detection of thesuction posture of the electronic component by the component imagepickup device 16, the shaft 10 is to be rotated by the actuator 15 tocorrect the deviation. In this stage, as shown in FIG. 14, a rotativedisplacement attributed to the bending of the shaft 10 occurs at thesuction nozzle tip, and therefore, a further displacement occurs.

SUMMARY OF THE INVENTION

In view of the aforementioned conventional issues, the present inventionhas an object to provide a component mounting method and apparatuscapable of achieving a high mounting accuracy without reducing theproductivity even with the existence of the bending of the shaft whichvertically and rotatively moves while being interlocked with the suctionnozzle.

In accomplishing these and other aspects, according to a first aspect ofthe present invention, there is provided a component mounting method.The method includes determining at a specified position a circuit boardon which a component is to be mounted, sucking a component from acomponent supply device by a suction nozzle which is mounted on a headsection and is able to move vertically and rotatively picking up by animage pickup device an image of the component sucked by the suctionnozzle, inspecting a sucked state of the component by analyzing thecaptured image using a recognition control device, and mounting thecomponent to the specified position on the circuit board whilecorrecting a mounting position according to a result of inspection. Themethod further includes capturing by the image pickup device a rotaryposture of a suction nozzle tip surface when the suction nozzlerotatively moves, before the component is mounted onto the circuitboard. A displacement of the suction nozzle tip surface is inspectedwhen the suction nozzle rotatively moves. Finally, the mounting positionof the component is corrected in a mounting stage according to thedisplacement of the suction nozzle tip surface.

According to a second aspect of the present invention, there is provideda component mounting method according first aspect, wherein rotarypostures of a suction nozzle tip surface when the suction nozzle movesrotatively and vertically are captured by the image pickup device,before the component is mounted onto the circuit board. In addition, thedisplacements of the suction nozzle tip surface are inspected when thesuction nozzle moves rotatively and vertically.

According to a third aspect of the present invention, there is provideda component mounting method according to the second aspect, whereindisplacements of the suction nozzle tip surface at a plurality of anglesof rotation of the suction nozzle and at upper and lower positions ofthe suction nozzle are inspected when the suction nozzle movesrotatively and vertically.

According to a fourth aspect of the present invention, there is provideda component mounting method according to the third aspect, whereindisplacements of the suction nozzle tip surface at angles of rotation of0 deg, 90 deg, 180 deg and 270 deg of the suction nozzle and at upperand lower positions of the suction nozzle are inspected when the suctionnozzle moves rotatively and vertically.

According to a fifth aspect of the present invention, there is provideda component mounting method according to the third aspect, wherein theupper position of the suction nozzle is a position where the suctionnozzle sucks a mountable component having a maximum component thickness,and the lower position of the suction nozzle is a position where thesuction nozzle sucks no component.

According to a sixth aspect of the present invention, there is provideda component mounting method according to the first aspect, wherein thecapturing, inspecting, and correcting are performed every time thesuction nozzle sucks a component.

According to a seventh aspect of the present invention, there isprovided a component mounting method according to the first aspect,wherein the rotary posture of the suction nozzle tip surface is capturedby the image pickup device before the mounting of components onto thecircuit board has begun. In addition, the displacement of the suctionnozzle tip surface is inspected when the suction nozzle movesrotatively. Furthermore, the mounting position of the component iscorrected in every mounting stage according to the displacement of thesuction nozzle tip surface.

According to an eighth aspect of the present invention, there isprovided a component mounting apparatus comprising: a component supplydevice having a plurality of component supply units; a circuit boardpositioning device for positioning at a specified position a circuitboard on which a component is to be mounted; a mounting head providedwith a head section which can be mounted with a suction nozzle and has afunction of making the mounted suction nozzle move rotatively operatingto suck to the suction nozzle a component from the component supplydevice and mount the component to the specified position on the circuitboard; an image pickup device for capturing a rotary posture of asuction nozzle tip surface when the suction nozzle moves rotativelybefore the component is mounted onto the circuit board; a calculatingsection for obtaining a displacement of the suction nozzle tip surfacewhen the suction nozzle moves rotatively based on the rotary posturecaptured by the image pickup device; and a control section forcorrecting the mounting position of the component in a mounting stageaccording to the displacement of the suction nozzle tip surface.

According to a ninth aspect of the present invention, there is provideda component mounting apparatus according to the eighth aspect, whereinthe image pickup device captures rotary postures of a suction nozzle tipsurface when the suction nozzle moves rotatively and vertically, beforethe component is mounted onto the circuit board. The calculating sectionobtains displacements of the suction nozzle tip surface when the suctionnozzle moves rotatively and vertically.

According to a tenth aspect of the present invention, there is provideda component mounting apparatus according to the ninth aspect, whereinthe calculating section obtains displacements of the suction nozzle tipsurface at a plurality of angles of rotation of the suction nozzle. Inaddition, upper and lower positions of the suction nozzle are inspectedwhen the suction nozzle moves rotatively and vertically.

According to an eleventh aspect of the present invention, there isprovided a component mounting apparatus according to the tenth aspect,wherein the calculating section obtains displacements of the suctionnozzle tip surface at angles of rotation of 0 deg, 90 deg, 180 deg and270 deg of the suction nozzle. In addition, upper and lower positions ofthe suction nozzle are inspected when the suction nozzle rotatively andvertically moves.

According to a twelfth aspect of the present invention, there isprovided a component mounting apparatus according to the tenth aspect,wherein the upper position of the suction nozzle is a position where thesuction nozzle sucks a mountable component having a maximum componentthickness, and the lower position of the suction nozzle is a positionwhere the suction nozzle sucks no component.

According to a thirteenth aspect of the present invention, there isprovided a component mounting apparatus according to the eighth aspect,wherein the control section controls operations of the image pickupdevice and calculating section so that the operations are performedevery time the suction nozzle sucks a component.

According to a fourteenth aspect of the present invention, there isprovided a component mounting apparatus according to the eighth aspect,wherein the image pickup device captures the rotary posture of thesuction nozzle tip surface before the mounting of components onto thecircuit board has begun. In addition, the calculating section obtainsthe displacement of the suction nozzle tip surface when the suctionnozzle rotatively moves. Finally, the control section corrects themounting position of the component in every mounting stage according tothe displacement of the suction nozzle tip surface.

According to the above construction, by preparatorily measuring thedisplacement of the suction nozzle tip according to the bending of theshaft when the suction nozzle moves vertically or vertically androtatively before the production of the circuit board, and by reflectingthe measurement result in producing the circuit board, the mountingaccuracy can be improved without any reduction in productivity due tothe excessive vertical movement for the recognition at the same heightas the mounting height.

According to the above construction, the apparatus can achieve a highmounting accuracy by implementing the above mounting method.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a flowchart of correction data forming a portion of a controlsequence according to an embodiment of the electronic component mountingmethod of the present invention;

FIG. 2 is a flowchart of a production process portion of the abovecontrol sequence;

FIG. 3 is an explanatory view of the suction nozzle height and theamount of displacement according to the component thickness of anelectronic component in the above embodiment;

FIG. 4 is an explanatory view of the amount of displacement according tothe angle of rotation of the suction nozzle in the above embodiment;

FIG. 5 is an explanatory view of jigs for use in the above embodiment;

FIGS. 6A and 6B are graphs showing relationships between the componentthickness and the nozzle tip displacement;

FIG. 7 is a perspective view showing the overall schematic constructionof a prior art electronic component mounting apparatus;

FIG. 8 is a flowchart of a control sequence according to an electroniccomponent mounting method;

FIG. 9 is a plan view of an example of a circuit board;

FIG. 10 is an explanatory view of an example of mounting data;

FIG. 11 is an explanatory view of an example of mark data;

FIG. 12 is a schematic diagram of a suction nozzle vertical and rotativemovement mechanism;

FIG. 13 is an explanatory view of a displacement attributed to shaftbending in the above embodiment;

FIG. 14 is an explanatory view of a rotative displacement attributed toshaft bending in the above embodiment; and

FIG. 15 is a schematic block diagram showing control section andcalculating section etc. of the electronic component mounting apparatusfor bringing out the method of the embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like reference numeralsthroughout the accompanying drawings.

An electronic component mounting method and apparatus according to oneembodiment of the present invention will be described below withreference to FIGS. 1 through 6. It is to be noted that the overallconstruction of the electronic component mounting apparatus and thecomponent mounting head are almost similar to those described inconnection with the prior art with reference to FIGS. 7 and 12, and thedescription for them should be referred to with no further descriptionprovided.

In the present embodiment, as shown in FIG. 1, prior to the productionof the circuit board, the displacement of the suction nozzle tip due tothe bending of the shaft when the suction nozzle moves vertically androtatively is measured by, for example, obtaining a displacement betweencenter positions obtained from an upper locus and a lower locus of thesuction nozzle rotation. Thereafter the production of the circuit boardis performed as shown in FIG. 2.

As shown in FIG. 3, since the height at which the suction nozzle ismoved down differs depending on the component thickness of theelectronic component 400, 401 to be mounted, the thickness of eachcomponent is required to detect the displacement of the nozzle tip.Accordingly, for the purpose of simplifying the control in the presentembodiment, the displacements of the nozzle tip in the case of amountable maximum component thickness Tmax and in the case of a minimumcomponent thickness Tmin (where no component is sucked, i.e., thecomponent thickness is zero) are measured. A value linearly approximatedfrom the displacement of the nozzle tip in the case of the componentthickness Tmax and in the case of the component thickness Tmin isapplied to the desired electronic component having a component thicknessT.

Further, as shown in FIG. 4, it is necessary to detect the displacementat every angle of rotation of the suction nozzle 9. In the presentembodiment, for the purpose of simplifying the control method, thedisplacements of the nozzle tip at the angles of rotation of 0 deg, 90deg, 180 deg and 270 deg of the suction nozzle 9 are measured, thedisplacement at the angle of rotation of 0 deg smoothed by averaging themeasurement results is derived, and a value obtained by rotationallytransforming the calculated displacement at the angle of 0 deg isapplied to the case of a desired angle of rotation.

For the measurement, as shown in FIG. 5, a jig A corresponding to thenozzle height in the case where an electronic component having acomponent thickness Tmax is sucked by the suction nozzle 9, and a jig Bcorresponding to the nozzle height in the case where an electroniccomponent having a component thickness Tmin is sucked, are used. Thenozzle tip position of the suction nozzle at the component recognitionheight is measured by the component image pickup device 16, and thenozzle tip position in the position of the mounting height is measuredby the image pickup device 17 whose image pickup focal point is locatedat the mounting height.

The measurement procedure is to firstly mount the jig A on the desiredhead section and position the jig tip at the component recognitionheight. A tip position (Xarec(θ), Yarec(θ)) of the jig A at each of theangles of rotation of 0 deg, 90 deg, 180 deg and 270 deg is measured bythe component image pickup device 16 (Step #10). Next, the jig tip ispositioned at the mounting height, and a tip position (XAmou(θ),Yamou(θ)) of the jig A at each of the angles of rotation of 0 deg, 90deg, 180 deg and 270 deg is measured by the image pickup device 17 (Step#11). In a similar manner, the jig B is mounted on the head section, anda tip position (Xbrec(θ), Ybrec(θ)) of the jig B at each of the anglesof rotation of 0 deg, 90 deg, 180 deg and 270 deg is measured by thecomponent image pickup device 16 (Step #12). Then, the jig tip ispositioned at the mounting height, and a tip position (XBmou(θ),YBmou(θ)) of the jig B at each of the angles of rotation of 0 deg, 90deg, 180 deg and 270 deg is measured by the image pickup device 17 (Step#13).

Next, nozzle tip, displacements (ΔXA, (θ), ΔYA(θ)) and (ΔXB(θ), ΔYB(θ))in the case where the suction nozzle is moved down from the componentrecognition height to the mounting height at each of the angles ofrotation of 0 deg, 90 deg, 180 deg and 270 deg are derived from theobtained measurement results for each of the component thickness Tmax(jig A) and the component thickness Tmin (jig B) according to thefollowing equations (Step #14). In this case, different image pickupdevices are used for the measurement of the component recognition heightand the mounting height. Therefore, for the purpose of making thecoordinate systems of the measurement results coincide with each otherat each height, we have a consideration with the center position of therotative movement of the suction nozzle, i.e., (ΣΔXArec(θ)/4,ΣΔYArec(θ)/4) and (ΣΔXBrec(θ)/4, ΣΔYBrec(θ)/4) at the componentrecognition height and (ΣΔXAmou(θ)/4, ΣΔYAmou(θ)/4) and (ΣΔXBmou(θ)/4,ΣΔBmpu(θ)/4) at the mounting height, used as a reference.

[In the case of component thickness Tmax (jig A)]

ΔXA(θ)=(XAmou(θ)−(ΣXAmou(θ)/4))−(XArec(θ)−(ΣXArec(θ)/4))  (1)

ΔYA(θ)=(YAmou(θ)−(ΣYAmou(θ)/4))−(YArec(θ)−(ΣYArec(θ)/4))  (2)

[In the case of component thickness Tmin (jig B)]

ΔXB(θ)=(XBmou(θ)−(ΣXBmou(θ)/4))−(XBrec(θ)−(ΣXBrec(θ)/4))  (3)

ΔYB(θ)=(YBmou(θ)−(ΣYBmou(θ)/4))−(YBrec(θ)−(ΣYBrec(θ)/4))  (4)

Further, the smoothed displacements (ΔX′A(0), (ΔY′A(0)) and (ΔX′B(0),(ΔY′B(0)) in the case where the suction nozzle is moved down from thecomponent recognition height to the mounting height at the angle ofrotation of 0 deg are derived from the equations (1) through (4) foreach of the component thickness Tmax (jig A) and the component thicknessTmin (jig B) according to the following equations (Step #15). It is tobe noted that the values of (ΔXA(0), ΔYA(0)) and (ΔXB(0), ΔYB(0))obtained from the aforementioned equations can also be used. However,the value obtained by smoothing the displacements of the nozzle tip atall the measured angles of rotation is used, taking into considerationthe case where the nozzle tip does not describe a perfect circle withthe rotation of the suction nozzle.

[In the case of component thickness Tmax (jig A)]

ΔX′A(0)=ΔXA(0)+(ΣΔXA(θ)/4)  (5)

ΔY′A(0)=ΔYA(0)+(ΣΔYA(θ)/4)  (6)

[In the case-of component thickness Tmin (jig B)]

ΔX′B(0)=ΔXB(0)+(ΣΔXB(θ)/4)  (7)

ΔY′B(0)=ΔYB(0)+(ΣΔYB(θ)/4)  (8)

Finally, FIGS. 6A, 6B are obtained from the equations (5) through (8),and the relationship of a displacement (ΔX′,ΔY′) between the componentthickness T and the nozzle tip at the angle of rotation of 0 deg of thesuction nozzle is derived according to the following equations (Step#16).

ΔX′=ΔX′B(0)+{(ΔX′A(0)−ΔX′B(0))/(Tmax−Tmin)}×(T−Tmin)  (9)

ΔY′=ΔY′B(0)+{(ΔY′A(0)−ΔY′B(0))/(Tmax−Tmin)}×(T−Tmin)  (10)

Therefore, the displacement of the nozzle tip at the angle of rotation θof the suction nozzle can be derived according to the followingequations by rotationally transforming the displacement at the angle ofrotation of 0 deg (Step #17).

ΔX=ΔX′ cos θ−ΔY′ sin θ  (11)

ΔY=ΔX′ sin θ−ΔY′ cos θ  (12)

These values differ for every head, and therefore, all the heads aresubjected to the same processing, thereby deriving a nozzle tipdisplacement (ΔXi, ΔYi) of the head i.

Next, the circuit board is produced by firstly forming mounting datafrom the mounting pattern of the circuit board to be produced before thestart of the production similar to the prior art (Step #1), and bydetecting a positional relationship between the mounting pattern and thetarget mark of the circuit board for reference use, thereby forming markdata (Step #2).

The subsequent processes in the production stage are similar to those ofthe prior art, and the processes will be described with reference toFIG. 2. First, the circuit board 1 to be produced is brought into thecircuit board positioning device 4 (Step #3). Next, the board imagepickup device 6 is aligned from above with the desired target mark 3 a,3 b, 3 c, etc. of the circuit board to pick up the image of the targetmark, thereby detecting the target mark position of the circuit board.According to this image pickup result, the mounting position and theangle are corrected (Step #4).

Subsequently, the desired electronic component is sucked by thecomponent supply device 8 at a mounting block k according to thepreparatorily formed mounting data (Step #5). The suction posture of thesucked electronic component is then picked up by the component imagepickup device 16, and the mounting position and the angle of theelectronic component are corrected based on this image pickup result(Step. #6). The mounting block k is determined by inserting a value of“0” into “k” of the mounting block number and then adding “1” to themounting block number “k” as shown in FIG. 2.

In this case, the suction nozzle is rotated to the mounting angle θthereafter the suction nozzle is moved down for the mounting of theelectronic component having the component thickness T on the circuitboard. In this stage, the displacement (ΔXi, ΔYi) of the nozzle tip ofthe head i is derived from the aforementioned equations (11) and (12),thereby determining the final mounting position (Step #18). Theelectronic component is mounted onto the circuit board 1 according tothe mounting position and the angle obtained through the above processafter positioning the suction nozzle to the obtained mounting positionand the angle (Step #7).

At this point of time, it is examined whether or not the production ofthe circuit board 1 has been completed (Step #8). When the productionhas been completed, the circuit board 1 is brought out of the circuitboard positioning device 4 (Step #9). When the production has not beencompleted at Step #8, the sucking and mounting processes of the nextelectronic component are performed (Steps #5 through #7 and #18). Then,at Step #40, when a next circuit board to which components are to bemounted is present, the flow returns to Step #3. If no, the productionis terminated.

According to the description of the aforementioned embodiment, based onthe displacements of the nozzle tip in the case of the mountable maximumcomponent thickness and that in the case where no component is sucked,i.e., the component thickness is zero, the displacement in the case ofthe electronic component having the desired component thickness T islinearly approximated. However, by applying a more precise approximationmethod or measuring the displacement of the nozzle tip having a moredetailed component thickness instead of the linear approximation, themounting accuracy can be further improved.

Furthermore, the displacement at the angle of rotation of 0 deg smoothedby averaging the displacements of the nozzle tip at the angles ofrotation of 0 deg, 90 deg, 180 deg and 270 deg of the suction nozzle isderived, and the value obtained by rotationally transforming the deriveddisplacement at the angle of 0 deg is applied to the case of the desiredangle of rotation. However, by measuring the displacement of the nozzletip at more detailed angles of rotation of the suction nozzle, or bystoring the displacement data at every desired angle of rotation, themounting accuracy can be further improved.

FIG. 15 is a schematic block diagram showing control section andcalculating section etc. of the electronic component mounting apparatusfor bringing out the method of the embodiment. That is, in FIG. 15,reference numeral 300 denotes a control section, 301 an image processingsection, 302 a calculating section, 303 a storing section, and 304 adriver. The control section 300 is connected to the image pickup devices16, 17, image processing section 301, calculating section 302, storingsection 303, circuit board positioning device 4, driver 304, electroniccomponent mounting head 7, and nozzle 9, etc. so as to control the aboveoperations.

As described above in detail, the image pickup devices 16, 17 capturethe images of the rotary postures of the suction nozzle tip surface wheneach of the suction nozzles 9 move rotatively and vertically (at leastrotatively,) before the component is mounted onto the circuit board. Theimage processing section 301 performs image processing of the imagesobtained in the image pickup device 16, 17 and inputs theimage-processed data into the storing section 303. The calculatingsection 302 calculates the displacement of the suction nozzle tipsurface when the suction nozzle 9 moves rotatively and vertically (atleast rotatively) based on the rotary posture images captured by theimage pickup devices 16, 17 and stored in the storing section 303. Basedon the calculated displacement, the control section 300 controls theoperation of the driver 304 so that the driver 304 drives a suitable oneof the XY robot 20 and actuators 11, 15 to correct the mounting positionof the component in the mounting stage according to the displacement ofthe suction nozzle tip surface.

The control section 300 also controls the positioning operation of thecircuit board positioning device 4, the bringing-in and bringing-outoperations of the board conveyance section 5, the various operations ofthe head 7 and the sucking operations etc. of the nozzle 9 and theoperations of other devices.

In the embodiment, as described above, the control section 300 cancontrol operations of the image pickup devices 16, 17 and calculatingsection 302 so as to be performed every time the suction nozzle 9 sucksa component.

Instead, the control section 300 can control the following operation.That is, the image pickup devices 16, 17 capture the rotary postures ofthe suction nozzle tip surface before the process of mounting componentsonto the circuit board 10 begins. The calculating section 302 obtainsthe displacement of the suction nozzle tip surface when the suctionnozzle 9 rotatively moves, and then inputs the displacement data intothe storing section 303 for teaching operation. The control section 300controls the driver 304 to correct the mounting position of thecomponent in every mounting stage according to the displacements of thesuction nozzle tip surface while utilizing the stored displacement data,without capturing the images and calculating the displacements everytime the nozzle 9 sucks a component to be mounted, as shown in FIG. 2 bydashed lines as a teaching process at step #18a. That is, thedisplacement data obtained before the component mounting begins isutilized for correcting the mounting position of the component in everymounting stage without performing the process at step #18.

As is apparent from the above description, according to the electroniccomponent mounting method and apparatus of the present invention, byderiving the displacement of the nozzle tip when the suction nozzlemoves vertically and rotatively using the component thickness and themounting angle prepared as parameters before the start of theproduction, and reflecting on the mounting position the displacementwhen the suction nozzle moves vertically and rotatively according to thecomponent thickness and the mounting angle of the electronic componentin the production stage, the mounting accuracy can be improved, so thata circuit board having a higher mounting can be produced.

The entire disclosure of Japanese Patent Application No. 9-158936 filedon Jun. 16, 1997, including the specification, claims, drawings, andsummary are incorporated herein by reference in its entirety.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

We claim:
 1. A component mounting apparatus comprising: a componentsupply device having a plurality of component supply units; a circuitboard positioning device for positioning at a specified position acircuit board on which a component is to be mounted; a mounting headprovided with a head section which can be mounted with a suction nozzleand has a function of making the mounted suction nozzle rotatively move,operating to suck to the suction nozzle a component from the componentsupply device and mount the component to the specified position on thecircuit board; an image pickup device for capturing a rotary posture ofa suction nozzle tip surface when the suction nozzle rotatively moves,before the component is mounted onto the circuit board; a calculatingsection for obtaining a displacement of the suction nozzle tip surfacewhen the suction nozzle rotatively moves based on the rotary posturecaptured by the image pickup device; and a control section forcorrecting the mounting position of the component in a mounting stageaccording to the displacement of the suction nozzle tip surface.
 2. Acomponent mounting apparatus according to claim 1, wherein the imagepickup device captures rotary postures of a suction nozzle tip surfacewhen the suction nozzle rotatively and vertically moves, before thecomponent is mounted onto the circuit board, and the calculating sectionobtains displacements of the suction nozzle tip surface when the suctionnozzle rotatively and vertically moves.
 3. A component mountingapparatus according to claim 2, wherein the calculating section obtainsdisplacements of the suction nozzle tip surface at a plurality of anglesof rotation of the suction nozzle and at upper and lower positions ofthe suction nozzle are inspected when the suction nozzle rotatively andvertically moves.
 4. A component mounting apparatus according to claim3, wherein the calculating section obtains displacements of the suctionnozzle tip surface at angles of rotation of 0 deg, 90 deg, 180 deg and270 deg of the suction nozzle and at upper and lower positions of thesuction nozzle are inspected when the suction nozzle rotatively andvertically moves.
 5. A component mounting apparatus according to claim3, wherein the upper position of the suction nozzle is a position wherethe suction nozzle sucks a mountable component having a maximumcomponent thickness and the lower position of the suction nozzle is aposition where the suction nozzle sucks no component.
 6. A componentmounting apparatus according to claim 1, wherein the control sectioncontrols operations of the image pickup device and calculating sectionso as to be performed every time the suction nozzle sucks a component.7. A component mounting apparatus according to claim 1, wherein theimage pickup device captures the rotary posture of the suction nozzletip surface before start of mounting components onto the circuit board;the calculating section obtains the displacement of the suction nozzletip surface when the suction nozzle rotatively moves; and the controlsection corrects the mounting position of the component in everymounting stage according to the displacement of the suction nozzle tipsurface.